Ditto. I still think that's the most mind-warping technophiliac anime in existence.

When it comes to something being singularly unique and memorable for it, Serial Experiments Lain is that thing.

Honorable mentions are Cowboy Bebop (on its own merits) and Neon Genesis Evangelion (also on its own merits, but also especially because a ton of amazing anime and manga we have now wouldn't exist without it).